Power input

The data logger requires a power supply. It can receive power from a variety of sources, operate for several months on non-rechargeable batteries, and supply power to many sensors and devices. The data logger operates with external power connected to the green BAT and/or CHG terminals on the face of the wiring panel. The positive power wire connects to +. The negative wire connects to -. The power terminals are internally protected against polarity reversal and high voltage transients.

In the field, the data logger can be powered in any of the following ways:

  • 10 to 18 VDC applied to the BAT + and – terminals
  • 16 to 32 VDC applied to the CHG + and – terminals

To establish an uninterruptible power supply (ClosedUPS Uninterruptible Power Supply. A UPS can be constructed for most data logger applications using ac line power, a solar panel, an ac/ac or ac/dc wall adapter, a charge controller, and a rechargeable battery.), connect the primary power source (often a transformer, power converter, or solar panel) to the CHG terminals and connect a nominal 12 VDC sealed rechargeable lead-acid battery to the BAT terminals. See Power budgeting for more information. The Status Table ChargeState may display any of the following:

  • No Charge - The charger input voltage is either less than +9.82V±2% or there is no charger attached to the terminal block.

  • Low Charge Input – The charger input voltage is less than the battery voltage.

  • Current Limited – The charger input voltage is greater than the battery voltage AND the battery voltage is less than the optimal charge voltage. For example, on a cloudy day, a solar panel may not be providing as much current as the charger would like to use.

  • Float Charging – The battery voltage is equal to the optimal charge voltage.

  • Regulator Fault - The charging regulator is in a fault condition.


Sustained input voltages in excess of 32 VDC on CHG or BAT terminals can damage the transient voltage suppression.

Ensure that power supply components match the specifications of the device to which they are connected. When connecting power, switch off the power supply, insert the connector, then turn the power supply on. See Troubleshooting power supplies for more information.

Following is a list of CR6 power input Closedterminals Point at which a wire (or wires) connects to a wiring panel or connector. Wires are usually secured in terminals by screw- or lever-and-spring actuated gates with small screw- or spring-loaded clamps. and the respective power types supported.

  • BAT terminals: Voltage input is 10 to 18 VDC. This connection uses the least current since the internal data logger charging circuit is bypassed. If the voltage on the BAT terminals exceeds 19 VDC, power is shut off to certain parts of the data logger to prevent damaging connected sensors or peripherals.

  • CHG terminals: Voltage input range is 16 to 32 VDC. Connect a primary power source, such as a solar panel or VAC-to-VDC transformer, to CHG. The voltage applied to CHG terminals must be at least 0.3 V higher than that needed to charge a connected battery. When within the 16 to 32 VDC range, it will be regulated to the optimal charge voltage for a lead acid battery at the current data logger temperature, with a maximum voltage of approximately 15 VDC. A battery need not be connected to the BAT terminals to supply power to the data logger through the CHG terminals. The onboard charging regulator is designed for efficiently charging lead-acid batteries. It will not charge lithium or alkaline batteries.

  • USB port: 5 VDC via USB connection. If power is also provided with BAT or CHG, power will be supplied by whichever has the highest voltage. If USB is the only power source, then the CS I/O port, the 12V and SW12V terminals will not be operational. When powered by USB (no other power supplies connected) Status field Battery = 0. Functions that will be active with a 5 VDC source include sending programs, adjusting data logger settings, and making some measurements.


The Status field Battery value and the destination variable from the Battery() instruction (often called batt_volt or BattV) in the Public table reference the external battery voltage. For information about the internal battery, see Internal battery.

Powering a data logger with a vehicle

If a data logger is powered by a motor-vehicle power supply, a second power supply may be needed. When starting the motor of the vehicle, battery voltage often drops below the voltage required for data logger operation. This may cause the data logger to stop measurements until the voltage again equals or exceeds the lower limit. A second supply or charge regulator can be provided to prevent measurement lapses during vehicle starting.

In vehicle applications, the earth ground lug should be firmly attached to the vehicle chassis with 12 AWG wire or larger.

Power LED indicator

When the data logger is powered, the Power LED will turn on according to power and program states:

  • Off: No power, no program running.
  • 1 flash every 10 seconds: Powered from BAT, program running.
  • 2 flashes every 10 seconds: Powered from CHG, program running.
  • 3 flashes every 10 seconds: Powered via USB, program running.
  • Always on: Powered, no program running.